Numerous attempts have been made to develop an apparatus to remove plaque or tartar from the surface of the teeth. Some of the previously developed apparatus includes the discharge of a water stream onto the teeth. Most of these devices suffer from lack of sufficient and effective power, such as caused by battery limitations. Several prior patents also claim their product produces "mild cavitations." This is an incorrect utilization of the technical term "cavitation."
The present invention uses hydrodynamic cavitation to produce therapeutic; radicals and ions in water to help eliminate and/or prevent periodontal diseases.
When a body of liquid is heated under constant pressure, or when its pressure is reduced at constant temperature by static or dynamic means, a state is reached at which vapor-filled micro-bubbles, become visible and grow. When vaporization is caused by heating, i.e. boiling, the change in state from liquid to vapor is slow because of the necessity to add heat, including the heat of vaporization. However, when the vapor is caused by quickly reducing the pressure on the liquid, such as expanding it through a nozzle, the vapor-filled micro-bubbles are rapidly formed.
The bubble growth is explosive because it is the result of vaporization to maintain conservation of energy. The condition is known as "cavitation" when it is caused by rapid pressure reduction at essentially constant temperature. Cavitation involves the entire sequence of events beginning with the bubble formation and extending through vapor bubble collapse.
In cavitated water, the heat from cavity implosion decomposes water into reactive hydrogen ions and hydroxyl radicals. Immediately following the breakdown, but at a slower rate, hydrogen ions and hydroxyl radicals recombine to form hydrogen peroxide and molecular hydrogen. Cavitation, thus, is a result of pressure reduction in the liquid and it can be controlled by controlling the amount of the pressure reduction. If the pressure is reduced and maintained for sufficient duration below a certain critical pressure (determined by the physical properties and initial pressure and temperature conditions of the liquid), it will produce cavitation.
Hydrodynamic cavitation is produced in this application when an aqueous solution at about 15 to 20 psig is forced through a nozzle into a vacuum of about 25" Hg. at the nozzle throat. A flow rate of approximately 1/8 gpm to 1/4 gpm will produce the desired cavitation effect.
Several methods of adjusting the degree of cavitation and thus the amount of OH radical output are available.
1. Cavitation pump output pressure. PA1 2. Change in the size of cavitation nozzle throat. PA1 3. Change in the core angle of the diffusion throat. PA1 4. Change in the length of the diffusion throat. PA1 5. Change in the length of the focusing applicator. PA1 6. Associated with methods of improving overall efficiency of the dental device would be adding cleansing or therapeutic solutions to the water tank. Such solutions might be diluted hydrogen peroxide and/or water soluble coenzyme CoQ10. PA1 (1) EPA/540/AR-93/520: "CAV-OX.RTM. CAVITATION OXIDATION PROCESS." PA1 (2) California Institute of Technology: Thesis "Ultrasonic Irradiation of Chemical Compounds in Aqueous Solutions." PA1 (3) Science, 20 Sep. 19091, Vol. 253, pg. 1397. PA1 (4) Scientific American, February 1989, pg. 80.
The phenomena of hydrodynamic cavitation has been demonstrated in many test series. For example, the following reports provide technical data and results in applications involving the removal of organic chemicals from aqueous solutions when the contaminants are in the ppb (parts per billion) range.
Further technical data can be found in Joseph Pisani U.S. Pat. Nos. 4,906,387 and 4,990,260 and in Dale W. Cox U.S. Pat. Nos. 5,326,468 and 5,494,585, the entire disclosures of which are incorporated herein by this reference.